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3. How many atoms in 3.91 moles of sodium?

Gala2k [10]

Answer:

Explanation:

The formula for sodium is Na. It does not form a molecule in some way.

1 mol Na = 6.02*10^23 atoms

3.91 mol = x Cross multiply

x = 3.91 * 6.02 * 10^23

x = 23.65 * 10^23

x = 2.365 * 10^24

Scientific notation is always expressed as a number 1 ≤ x < 10

3 0

3 years ago

Arrange the processes of the water cycle in the correct order, starting with the heat from the Sun.

tensa zangetsu [6.8K]

There are four processes in water cycle. Starting from the heat from the sun is the process of evaporation.

Evaporation: In this process, light from the sun evaporate water from oceans, rivers, lakes, ice and soil into water vapor. Water vapor molecules combine to form clouds.

Condensation: In this process, water vapor from clouds cool down and turns back into liquid water in the form of water droplets. These water droplets stays in the air. Precipitation: In this process, water droplets they combine in the air, they become too heavy to stay in the air. Therefore, they fall in the form of rain, snow or other form.

Collection: In this process, water that falls as rain, snow or other form comes back in the ocean, lakes, river or any other water body. Water will also be absorbed by soil and will be collected as ground water.

;D

3 0

3 years ago

Whats Orbital Notation for sodium

Tema [17]

Answer:

The p orbital can hold up to six electrons. We'll put six in the 2p orbital and then put the remaining electron in the 3s. Therefore the sodium electron configuration will be 1s22s22p63s1.

Explanation:

5 0

2 years ago

A certain radioactive isotope decays at a rate of 0.2% annually. Determine the half-life of this isotope, to the nearest year

pychu [463]

Answer:

The half-life of the radioactive isotope is 346 years.

Explanation:

The decay rate of the isotope is modelled after the following first-order linear ordinary differential equation:

$\frac{dm}{dt} = -\frac{m}{\tau}$

Where:

$m$ - Current isotope mass, measured in kilograms.

$t$ - Time, measured in years.

$\tau$ - Time constant, measured in years.

The solution of this differential equation is:

$m(t) = m_{o}\cdot e^{-\frac{t}{\tau} }$

Where $m_{o}$ is the initial mass of the isotope. It is known that radioactive isotope decays at a yearly rate of 0.2 % annually, then, the following relationship is obtained: